Vibrational Circular Dichroism of Thiolate-Protected Au25 Clusters: Accurate Prediction of Spectra and Chirality Transfer within the Mixed Ligand Shell

We have prepared Au25(PET)18-2x((R)-FBI-NAS)x(PET = 2-phenylethylthiol, (R)-FBINAS = (R)-5,5',6,6',7,7',8,8'-octafluoro-[1,1'-binaphthalene]-2,2'-dithiol) mixed ligand shell clusters via ligand exchange. Two fractions with different composition of the ligand shell were separated using size-exclusion chromatography and studied by infrared (IR) spectroscopy and vibrational circular dichroism (VCD). Both IR and VCD spectra are dominated by FBINAS vibrations although PET is more abundant on the cluster. Calculated VCD spectra on a model cluster Au25(SH)16(FBINAS)1 depend on the charge state of the cluster, and the anion is in excellent agreement with the experimental spectra of the Au25(PET)18-…